FIG. 23 is a block diagram of conventional electronic device 1. Electronic device 1 includes detection means 2, pattern data output means 3, and comparison and determination means 4. Detection means 2 detects a movement of a writing tool when a signature is written. Pattern data output means 3 generates signature data of movement of the writing tool according to detection results from detection means 2. Comparison and determination means 4 compares the signature data generated by pattern data output means 3 with signature data of a preregistered signatory to authenticate the signatory. Detection means 2 includes a position detection means for a tablet type input device for instance, or a video camera.
Patent literature 1 describes a conventional electronic device similar to electronic device 1.